fixup! doc: use serial comma in fs docs

doc/api/fs.md

@@ -1559,7 +1559,7 @@ changes:
 * Returns: {Promise} Fulfills with `undefined` upon success.
 
 Asynchronously writes data to a file, replacing the file if it already exists.
-`data` can be a string, a buffer, an {AsyncIterable} or {Iterable} object.
+`data` can be a string, a buffer, an {AsyncIterable}, or an {Iterable} object.
 
 The `encoding` option is ignored if `data` is a buffer.